U.S. patent number 4,634,310 [Application Number 06/700,874] was granted by the patent office on 1987-01-06 for traffic marker and housing.
Invention is credited to Ronald A. W. Clarke.
United States Patent |
4,634,310 |
Clarke |
January 6, 1987 |
Traffic marker and housing
Abstract
A traffic marker and housing is disclosed, intended for
installation in a road surface to provide delineation of traffic
lanes. The marker comprises a platform installed flush with the
road surface, with two bridges projecting upwardly from the
platform, the bridges including ramp portions, and a reflector
carried between the bridges in protected fashion. The platform
extends beyond the ends of the bridges. The two bridges are aligned
with the direction of traffic flow and offset from each other by an
angle corresponding to the angle presented by an oncoming snowplow
blade, so that the snowplow blade impacts both substantially
simultaneously. The ramp portions are coplanar, and the plane of
the ramp portions is offset by the same angle as the bridges.
Apertures in the bridges provide an automatic cleaning feature,
produced by the effect of passing vehicles. The bridges have angled
outside edges to minimize inconvenience to traffic.
Inventors: |
Clarke; Ronald A. W. (London,
Ontario, CA) |
Family
ID: |
4127187 |
Appl.
No.: |
06/700,874 |
Filed: |
February 12, 1985 |
Foreign Application Priority Data
Current U.S.
Class: |
404/15;
404/16 |
Current CPC
Class: |
E01F
9/553 (20160201) |
Current International
Class: |
E01F
9/06 (20060101); E01F 9/04 (20060101); E01F
009/00 () |
Field of
Search: |
;404/6,8,9,11,12,13,14,7,10,15,16 ;40/612 ;116/63R ;350/97,103
;248/346,519,677 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Assistant Examiner: Smith; Matthew
Claims
What is claimed as the invention is:
1. Traffic marker, having a reflector which reflects light from the
headlamps of an oncoming vehicle back towards the vehicle;
where a longitudinal axis of the marker lies parallel to the
direction of the traffic;
where the marker comprises a ramp-surface;
where the ramp surface is so positioned on the marker that an
oncoming snow-plow blade will strike the ramp-surface;
where the ramp-surface slopes gently upwards in such a manner that
the said snow-plow blade, upon striking the ramp-surface, will be
deflected gently up and over the marker;
and where the ramp surface also slopes laterally, at a substantial
angle to the longitudinal axis of the marker.
2. Marker of claim 1, where the said substantial angle is about 55
degrees.
3. Marker of claim 1, where the ramp surface is in two portions,
and where the reflector lies between the two portions.
4. Marker of claim 1, where the marker includes a platform, and
where the ramp surface is so arranged on the marker that the ramp
surface slopes upwards from the platform.
5. Marker of claim 4, where the platform extends forwards beyond
the ramp-surface, whereby an oncoming snow-plow blade is a
substantial distance onto the platform before striking the
ramp-surface.
Description
BACKGROUND OF THE INVENTION
This invention relates to road-imbedded traffic markers and their
housings, including especially traffic markers embodying
reflectors.
Traffic markers are installed in roads for the purpose of providing
positive visual identification or delineation of the various
traffic lanes at night, which is especially useful in wet or foggy
conditions. Traffic lanes are usually defined by lines painted on
the road surface, but in wet weather conditions the painted lines
often become quite indiscernable, because of the deflection of the
vehicles' headlight beams away from their source. To resolve this
problem, reflectors are installed, with reflective surfaces
protruding above the water film covering the road surface. When
there are heavy snowfalls, the lines may become covered with snow.
Road-imbedded traffic markers project slightly above the road
surface and thus reduce or eliminate the problem, especially when
embodying reflective elements.
Generally, road markers are positioned in line with the lines
painted on the road surface, so that the lanes are thus clearly
delineated. In addition, since the noise and vibration produced
from driving over the markers deters drivers from doing so, there
is then reduced wear on the painted markings, reducing the need for
frequent repainting.
However, there are a number of problems associated with designing
suitable traffic markers, especially in areas where snowfalls
commonly occur. Any traffic marker must be able to stand up to
repeated impacts from vehicle tires. In the case of traffic markers
in snowfall areas, the markers must also be able to withstand the
impact of snow removal equipment, especially snowplow blades, and
at the same time must not unduly impede snow removal or produce
excessive wear or damage to snowplow blades. The marker housing
itself must be able to withstand impact, and the reflector should
be protected to avoid separation from the housing, which has been a
problem in the prior art.
Also, a traffic marker should preferably support its reflective
surface or surfaces at approximately ninety degrees to the light
source, i.e. approximately vertically. If the surface is angled,
some light is inevitably reflected away from the source rather than
back towards it, reducing the brilliance of the return signal and
thus the effectiveness of the marker. There must also be some means
by which the reflective surfaces are kept relatively clean, so that
their reflective properties are preserved. In the case of a
vertical reflective surface, this is particularly difficult to
accomplish since road debris tends to pile up and accumulate
against the surface. A reflective surface with an angled face is to
some extent cleaned by the action of vehicles' wheels passing over
it.
In some traffic markers in the prior art, cleaning of the
reflective surfaces has been accomplished by providing for vertical
movement of components when impacted, to wipe the reflective
surfaces. Vertical movement has also been employed in the prior art
to protect the markers by having them recede towards or beneath the
road surface on impact, such markers being referred to as being
"retractable".
Ideally the traffic markers should not be too complicated or
expensive to manufacture, in view of the large quantities required.
Retractable markers are obviously somewhat complicated in design.
The markers should also be relatively simple to install in the road
surface. Simplicity of installation is important not only from a
cost viewpoint, but also in view of the need to minimize disruption
to traffic during installation.
SUMMARY OF THE INVENTION
In view of the above problems, it is an object of the present
invention to provide an improved traffic marker and housing.
Thus in accordance with the present invention there is provided a
traffic marker housing which is plowable, which protects and
supports a reflector or reflectors, and which in its preferred
embodiment provides for automatic cleaning of the reflector or
reflectors. The marker is relatively simple in design, and is
relatively simple to install.
As will be described in greater detail later herein, the marker
housing comprises a platform for installation at the level of the
road surface, with two bridges projecting upwardly from the
platform and a reflector carried between the bridges. The bridges
are shaped to approximately complement the shape presented by an
oncoming snowplow blade, which contacts the bridges and rides over
them and thus above the reflector.
In accordance with the automatic reflector cleaning feature of the
invention, an outlet is provided adjacent to each reflector through
a bridge. The opening operates in the manner described later herein
to provide an automatic cleaning action when vehicles pass by.
Other features of the invention will become apparent in the
following detailed description of the preferred and alternative
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to the accompanying drawings, in which:
FIG. 1 is a perspective, showing the preferred embodiment of the
traffic marker mounted in a road surface, and showing locating
dowels used in the installation of the marker but removed after
installation;
FIG. 2 is a side elevation of the marker;
FIG. 3 is an end elevation of the marker;
FIG. 4 is a plan view of the marker;
FIG. 5 is a sectional drawing along the line A--A of FIG. 4;
FIG. 6 is a side elevation of an alternative embodiment, intended
for one-way traffic;
FIG. 7 is a plan view of the alternative embodiment;
FIG. 8 is a side elevation of the marker, showing an alternate
anchoring means for the marker housing;
FIG. 9 is an end elevation of the marker, also showing the
alternate anchoring means; and
FIG. 10 is a drawing of a reflector holder.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, the preferred embodiment of the traffic
marker of the present invention is illustrated. The marker 1
consists essentially of a housing 2 and reflectors 3, one facing
each traffic direction. The housing 2 comprises a platform 4 and
two bridges 6 running parallel to the traffic flow. The reflectors
are mounted vertically in the housing, for optimum reflection, and
the marker is fixed rather than retractable, offering relative
simplicity. As will be explained in more detail herein, the
reflectors are essentially self-cleaning, despite its vertical
orientation and the absence of moving parts.
The preferred embodiment is intended for two-way traffic. Thus the
bridges have ramp portions 7 in both traffic directions, and two
reflectors (or a single two-sided reflector). The marker is
reversible, i.e. it may be oriented in either direction, unless of
course it is desired to have different reflector signals (i.e.
different colours) sent in different directions.
The platform 4 is installed, in the manner described later herein,
with its upper surface essentially flush with the road surface 5.
The bridges 6 project above the road surface, as do the reflectors
3 which are mounted vertically and centrally between the
bridges.
The type of reflector 3 is not in itself important to the present
invention, nor is the means by which the reflectors are mounted
between the bridges. Any suitable reflector may be employed, and
any suitable mounting means may be employed. In the preferred
embodiment of the present invention, the reflector is a Stimsonite
(trademark) reflector, manufactured and sold by the Signal Products
Division of Amerace Corporation. As illustrated in FIG. 10, two
such reflectors 3 are bonded into a reflector holder 8, with one
reflector facing each direction. The bottom surface 11 of the
reflector holder is in turn bonded to the marker platform 4, the
platform being provided with a recess 13 to accommodate the
holder.
Alternatively, a Stimsonite 944 (trademark) reflector having angled
faces may be used. The bottom surface of this reflector fits within
the recess 13 and is there bonded to the platform. The automatic
cleaning feature described later herein is inoperative when such a
reflector is used, but as mentioned earlier angled-face reflectors
are to some extent automatically cleaned by vehicle tire
action.
The main purpose of the bridges is to lift the blade of a snowplow
when the blade impacts the marker, so that the blade does not come
into contact with the reflector. The bridges are designed to
provide optimum performance under typical snowplowing conditions,
which are as follows:
a. Snowplowing speed: less than 70 kilometers per hour;
b. Blade mass: Approximately 2400 pounds or 1100 kilograms;
c. Angle of blade to direction of travel: approximately 55
degrees;
d. Angle of blade from road surface: approximately 55 degrees;
e. Blade leading edge material: tungsten carbide.
In view of the above parameters, the shape of the bridges is
somewhat complex, being designed to complement the shape presented
by a passing snowplow blade, whether passing from one direction or
the other. For convenience and clarity, the bridge design will now
be described with reference to one end or half of the marker only,
the other end or half being identical. FIGS. 2, 3, 4 and 5 most
clearly illustrate the bridge design.
The bridges 6 are offset from each other at an angle B of 55
degrees from the centre line of the marker, to correspond to the
usual snowplow blade angle. When a snowplow blade impacts the
marker, the first point of contact is the bridges, since they
project above the road surface. Because the bridges are offset at
55 degrees, the snowplow blade impacts both bridges virtually
similtaneously. The ramp portions 7 of the bridges are coplanar,
and the plane of the ramps is also offset by 55 degrees, so a
passing snowplow blade contacts planar surfaces of both bridges.
The shock load is thus fairly evenly distributed, and a relatively
large surface area is presented to the snowplow blade, thereby
reducing the pressure.
The ramp portions 7 rise from the platform at a suitably small
angle, such as 5 degrees. Obviously, too large an angle produces
too violent an impact with passing snowplow blades, while too small
an angle produces a marker which is longer than necessary (and
therefore more expensive to manufacture and install).
The ramp portions 7 of the bridges 6 do not start at the leading
edge 10 of the platform 4. In designs where bridges do start at the
leading edges of the platform, the force of the snowplow blade
impact acting relatively near the edge of the platform tends to
produce excessive flexing of the platform, frequently causing the
grout bond by which the marker is held in the road surface to fail.
In the present design, with the initial snowplow blade impact point
being more central (averaging roughly one sixth of the length of
the platform in from the leading edge of the platform), there is
less flexing of the platform, and the grout bond is accordingly not
so prone to failure. Another result of this extended leading edge
of the platform is of course that a larger surface area is provided
for bonding the housing to the road surface substrate, thus
improving the strength of the bond.
As can be seen most clearly from FIG. 3, the outside edges 14 of
the bridges 6 are angled at 45 degrees. These angled edges are
provided to minimize the obstruction and inconvenience to vehicular
traffic under ordinary weather conditions. The geometry of the
arrangement is such that the bridges present their maximum width to
the snowplow blade at the crucial point of initial contact,
becoming narrower due to the angled edges 14 as their height
increases.
The dimensions of the marker are of course not critical, and may be
varied considerably within the scope of the invention. However, it
has been found to be convenient to have the overall platform
dimensions to be about 141/2 inches long by 4 inches wide (36.8 cm.
by 10 cm.), with the top of the bridges projecting about 1/2 inch
(1.25 cm.) above the road surface.
The material preferably used for the construction of the marker
housing is a foundry zinc alloy, although any suitably strong
material could be used.
The bridges 6 are each provided with an outlet 16 centrally located
adjacent to each reflector 3 and the upper surface of the platform
4, by which water and other matter may escape from the platform.
The outlet for each reflector is through the bridge on the side of
the traffic facing that reflector. These outlets provide the
previously-mentioned automatic cleaning of the reflectors. In wet
weather, the wheel of an approaching vehicle sends out a bow wave
of water which enters the platform between the bridges. The water
is trapped between the bridges, and swirls in turbulent fashion
against the face of the reflector 3, thus cleaning the reflector.
The water then escapes via the outlet, being aided in doing so by
the partial vacuum created in the wake of the passing vehicle.
In dry conditions, the same action prevents dust and other debris
from accumulating against the reflector face.
FIGS. 6 and 7 illustrate an alternative embodiment, intended for
one-way traffic (although the preferred embodiment could of course
also be used for one-way traffic). As can be seen from the
drawings, all of the same features are employed, but only one
reflector direction is accommodated. The ramp portions 7 of the
bridges at one end or half of the marker, instead of continuing
into ramp portions for another half of the marker, terminate at an
angled rear surface 12 of the housing. The preferred embodiment can
be seen as two identical traffic marker "sections" abutting each
other and facing in opposite directions, with the alternative
embodiment being a singled marker section.
To install the marker in the road surface, a recess is excavated to
accommodate the marker housing, the recess preferably being no
larger than necessary to just accommodate the marker. A cutting
machine of the type described in U.S. Pat. No. 3,904,245, invented
by the present inventor and known as a reflex percussive cutting
machine, may be used, or any other suitable means may be employed.
A small measured quantity of hot bitumen or other suitable sealant
adhesive is then poured into the recess to act as a grout. A marker
is then inserted in the recess, locating dowels 40 having first
been inserted in dowel-receiving holes 42 provided in the outer
sides of the bridges 6. The dowels support the marker at the proper
height relative to the road surface while the grout is allowed to
set properly. Once the grout has set, the dowels are removed, and
then traffic may be allowed.
As seen most clearly in FIG. 5, the platform 4 has angled side
edges 44, angled inwardly at 30 degrees from the vertical to aid in
anchoring the platform in the grout. As illustrated in FIGS. 8 and
9, an alternate construction for the bottom of the platform may
instead be used, in which rows of angled tongues 46 project
downwardly to aid in anchoring the platform in the grout. The exact
anchoring means used is of course not essential to the
invention.
It will be appreciated that the above description of the preferred
and alternative embodiments is by way of example only. A number of
variations would be obvious to those skilled in the art, and would
still clearly be within the broad scope and spirit of the
invention, whether or not expressly described and claimed.
For example, it should be apparent that the above description
relates to a traffic marker for use in countries where vehicles
drive on the right hand side of the road. In countries where
vehicles drive on the left, the marker configuration would be a
mirror image of that described above.
Furthermore it should be apparent that the 55 degree bridge offset
angle was selected to match the typical angle of a snowplow blade
from the direction of traffic. In areas where different snowplow
blade angles are more common, a person skilled in the art could
readily adjust the design to a more suitable angle.
* * * * *